A new air agreement between the United States and Mexico signed last year went into effect last month, and the move could open up new opportunities for traveling to and from the countries. The agreement allows “the ability for an unlimited number of airlines to operate routes between cities,” reports Travel + Leisure. Before the agreement went into effect, only two to three airlines were allowed to serve each city pair, so flight options were limited, according to Thomas Engle, deputy assistant secretary for transportation affairs, U.S. Department of State. Now, several airlines are interested in entering the market or expanding their presence, including major U.S. carriers like Southwest Airlines and JetBlue. Low-cost carriers in Mexico are expressing interest, too. Passengers may soon have more options, which could help keep prices down. “Mexico is one of the biggest sources of inbound tourism for America,” Engle told Travel + Leisure. Engle said preliminary data from the Department of Commerce shows the United States saw more than 18 million tourists from Mexico last year. They spent about $19 billion when visiting.